1. Field of the Invention
The present invention relates to a reciprocating compressor, and more particularly to a reciprocating compressor having a structure for reducing a pulsation that is generated during a refrigerant discharge.
2. Description of the Related Art
Generally, a reciprocating compressor is widely used in freezing appliances such as refrigerator, or the like, to compress refrigerant.
As shown in FIG. 1, the reciprocating compressor includes a casing 10 having an upper shell 11 and a lower shell 12, a compressing device portion formed in a lower portion of the casing 10 and having components for compressing refrigerant, and an electric device portion 20 for driving the components of the compressing device portion.
The electric device portion 20 includes a stator 21, a rotator 22 rotated by an electro-magnetic operation with the stator 21, and a crank shaft 23 press-fitted in the center portion of the rotator 22.
The compressing device portion includes a cylinder block 30 disposed in the lower portion of the casing 10, a connecting rod 40 eccentrically connected to a lower end of the crank shaft 23, a piston 50 connected to a leading end of the connecting rod 40 to linearly reciprocate within a compressing chamber 31 defined in the cylinder block 30, and a cylinder head 60 disposed on a front side 32 (FIG. 2) of the cylinder block 30 for sealing the compressing chamber 31. The cylinder head 60 (FIG. 1) has a refrigerant intake chamber 61 and a refrigerant discharge chamber 62 formed at upper and lower portion thereof, respectively. Between the cylinder head 60 and the front side 32 of the cylinder block 30, a valve assembly 70 is disposed. The valve assembly 70 controls a flow rate of the refrigerant between the refrigerant intake chamber 61 and the compressing chamber 31 and also between the refrigerant discharge chamber 62 and the compressing chamber 31.
Meanwhile, at an upper portion of the cylinder head 60, an intake muffler 80 is disposed, intercommunicating with the refrigerant intake chamber 61. The intake muffler 80 is connected to a refrigerant intake pipe 81, through which the refrigerant is drawn from an evaporator (not shown).
As shown in FIGS. 2 and 3, a discharge muffler 33 protrudes from a lower surface of the cylinder block 30, and a muffler cover 34 provides a cover for sealing the discharge muffler 33. The muffler cover 34 is connected to a refrigerant discharge pipe 35 through which the refrigerant is fed to a condenser (not shown). On the front side 32 of the cylinder block 30, a refrigerant discharge port 32a is formed, intercommunicating with the discharge muffler 33 through a refrigerant channel 37.
Meanwhile, the valve assembly 70 includes an intake valve plate 71 having an intake valve 71a formed thereon, and a discharge valve plate 72 having a discharge valve 72a formed thereon. The intake valve 71a controls the flow rate of the refrigerant between the compressing chamber 31 and the refrigerant intake chamber 61 of the cylinder head 60, while the discharge valve 72a controls the flow rate of the refrigerant between the compressing chamber 31 and the refrigerant discharge chamber 62 of the cylinder head 60.
In the compressor constructed as above, the discharge of the refrigerant after being compressed by the piston is as follows:
First, the piston is retreated in the compressing chamber 31 by the rotation of the crank shaft 23 to a bottom dead center (to a left hand side of FIG. 1), and low temperature and low pressure refrigerant is fed from the evaporator (not shown). The refrigerant sequentially passes through the intake muffler 80 and the refrigerant intake chamber 61 of the cylinder head 60, and flows into the compressing chamber 31. Next, by the rotation of the crank shaft 23, the piston 50 is advanced in the compressing chamber 31 to a top dead center (right hand side of FIG. 1), and accordingly the refrigerant is compressed to high temperature and high pressure refrigerant. The compressed refrigerant stays in the refrigerant discharge chamber 62 of the cylinder head 62 for a predetermined time, and flows to the discharge muffler 33 through the refrigerant discharge port 32a and the refrigerant channel 37. Then, the high temperature and high pressure refrigerant is discharged to the condenser (not shown) through the refrigerant discharge pipe 35 that is connected to the muffler cover 34.
In the above reciprocating compressor, however, since the refrigerant is drawn, compressed, and discharged by the reciprocating movement of the piston 50 in the compressing chamber 31, the consistent discharge of the refrigerant can not be guaranteed. Accordingly, a discharge pulsation of the refrigerant occurs. The discharge pulsation of the refrigerant causes noise and vibration of the compressor. In particular, the noise produced in a frequency range of 120 Hz-500 Hz, which is a characteristic frequency of the components of the freezing appliance, causes resonance with the components, and increases the level of noise and vibration of the freezing appliance.
The discharge pulsation of the refrigerant can be reduced by increasing a streaming resistance of the discharged refrigerant. That is, by reducing a sectional area of the refrigerant channel 37 between the refrigerant discharge chamber 62 and the discharge chamber 33, or by lengthening the refrigerant channel 37, the discharge pulsation of the refrigerant can be reduced. However, making the cross-sectional area of the refrigerant channel 37 smaller hinders smooth refrigerant flow between the refrigerant discharge chamber 62 and the discharge muffler 33. Accordingly, the compressing efficiency deteriorates. Further, since the refrigerant channel 37 is passed through the interior of the cylinder block 30, the length of the refrigerant channel 37 is limited.
The present invention has been made to overcome the above-described problems of the related art, and accordingly, it is an object of the present invention to provide a reciprocating compressor having an improved refrigerant discharging structure, capable of reducing a discharge pulsation of refrigerant without dropping compressing efficiency of the refrigerant compressor.
The above object is accomplished by a reciprocating compressor according to the present invention, including a pair of discharge mufflers disposed on the lower portion of a cylinder block; a first and a second refrigerant channels interconnecting the pair of discharge mufflers and a refrigerant discharge chamber of a cylinder head; a pair of muffler covers for sealing the pair of discharge mufflers, respectively; a connecting pipe for connecting the pair of muffler covers with each other; and a refrigerant discharge pipe connected to one of the pair of muffler covers that is interconnected with the second refrigerant channel. The first and the second refrigerant channels have refrigerant inflow sides which are connected to the refrigerant discharge chamber and have a predetermined cross-sectional area, and refrigerant outflow sides which are connected to the pair of discharge mufflers and have a cross-sectional area smaller than the cross-sectional area of the refrigerant inflow sides. A discharge pulsation of refrigerant is reduced by varying a proportion between the cross-sectional areas of the refrigerant outflow side of the first refrigerant channel, the refrigerant outflow side of the second refrigerant channel, and the connecting pipe according to an exhaust air volume of the compressor, respectively.
In the reciprocating compressor having exhaust air volume of 3.0 cc, it is preferable that the relationship between a cross-sectional diameter of the refrigerant outflow side of the first refrigerant channel, the cross-sectional diameter of the refrigerant outflow side of the second refrigerant channel, and an inner diameter of the connecting pipe is expressed approximately by 2:2:1.8. More specifically, when the sectional diameter of the refrigerant inflow sides of the first and the second refrigerant channels are 6.4 mm, respectively, the cross-sectional diameter of the refrigerant outflow side of the first refrigerant channel is 2.0 mm, and the cross-sectional diameter of the refrigerant outflow side of the second refrigerant channel is 2.0 mm, and the inner diameter of the connecting pipe is 1.78 mm.
In the reciprocating compressor having exhaust air volume of 3.7-4.3 cc, a relationship between the cross-sectional diameter of the refrigerant outflow side of the first refrigerant channel, the cross-sectional diameter of the refrigerant outflow of the second refrigerant channel, and the inner diameter of the connecting pipe is expressed approximately by 2:3.5:1.8. Accordingly, when the cross-sectional diameter of the refrigerant inflow sides of the first and the second refrigerant channels are 2.0 mm, respectively, the cross-sectional diameter of the refrigerant outflow side of the second refrigerant channel is 3.5 mm, and the inner diameter of the connecting pipe is 1.78 mm.
In the reciprocating compressor having exhaust air volume of 5.2-6.2 cc, a relationship between the cross-sectional diameter of the refrigerant outflow side of the first refrigerant channel, the cross-sectional diameter of the refrigerant outflow side of the second refrigerant channel, and the inner diameter of the connecting pipe is expressed approximately by 2:3.5:2.2. Accordingly, when the cross-sectional diameters of the refrigerant inflow sides of the first and the second refrigerant channels are 6.4 mm, respectively, the cross-sectional diameter of the refrigerant outflow side of the first refrigerant channel is 2.0 mm, and the cross-sectional diameter of the refrigerant outflow side of the second refrigerant channel is 3.5 mm, and the inner diameter of the connecting pipe is 2.16 mm.
Meanwhile, it is preferable that the connecting pipe has bent ends formed on both ends at a predetermined angle and inserted in the pair of muffler covers toward inner walls of the muffler covers.